A key 20 in a conventional keyboard, as shown in FIG. 4, comprises a metal base 81, a conductive film 82, a plastic plate 83, an elastic member 84, a frame 85 and a cap 86. Moreover, corresponding coupling parts 811 and 861 are arranged on the metal base 81 and the cap 86, respectively. The frame 85 comprises a first rack 851 and a second rack 852 pivotably connected to each other. Two locking parts 853 and 854 corresponding to the coupling part 811 and 861 of the metal plate 81 and cap 86 are arranged on the first rack 851 and the second rack 852, respectively, whereby the cap 86 moves upward and downward.
However, the conventional keys 20 lie on the elastic member 84 and have no supporting elements on lateral sides thereof. Thus, the keys 20 may experience instability, i.e., shaking, when being pressed.